A Combined Experimental-Numerical Method for Determining the Heat Transfer Coefficient at a Fluid Flowing Molten Copper-Casting Mold Interface

Ascertaining the heat transfer coefficient (HTC) at the interface between molten copper alloy in a fluid flow state and a casting mold is more difficult than merely determining the coefficient in a cooling state after solidification is complete. This study therefore proposes a new method to measure the HTC at the interface between the flowing molten copper alloy and the casting mold. In this method, molten metal is poured into the mold tilted to the ground. A graph of the time-casting mold temperature increase rate is experimentally obtained during molten copper flowing. Then, a thermal simulation based on the experiment is conducted while varying the HTC to obtain the time-casting mold temperature increase rate graph numerically. Both time-casting mold temperature increase rate graphs are subsequently superimposed to determine one simulated time-casting mold temperature increase rate curve that agrees best with that of the experiment. The HTC of that curve is regarded as the interfacial HTC between the molten metal and the casting mold. The proposed method was applied to obtain the HTC at the interface between molten oxygen-free copper in the flowing state and the graphite casting mold. Thereby, 16,000-24,000 W/m(2) K was obtained. This HTC value agreed well with the theoretically calculated value of 23,146 W/m(2) K. This result demonstrated that the proposed method can be used to obtain the HTC at the interface between the flowing molten copper alloy and the casting mold.